MIAMI -- For the first time in a U.S. presidential campaign, candidates vying for the Democratic nomination will take part in a debate Sunday that will be broadcast across the U.S. in Spanish. The event, held at the University of Miami and broadcast by the Univision Network, marks the Democratic candidates' recognition of the growing political muscle that the country's more than 44 million Hispanics could wield in the 2008 election. Seven of the eight Democratic candidates will be taking part in the debate — including front-runners Sen. Hillary Rodham Clinton of New York, Sen. Barack Obama of Illinois and...